This invention relates to a construction for reducing wind and breath noise in microphones, and more particularly it relates to an assembly for reducing the sensitivity of sall diameter microphones to the interference cause by air passage from wind or breath.
A problem common to all microphones is the existence of substantial noise produced from air passage over the microphone's surface. Noise produced by wind passage over the microphone is commonly referred to as "puff", and noise produced by the passage of a person's breath over the microphone surface is commonly referred to as "pop". In the prior art, numerous methods have been employed to protect against both puff and pop, including the placement of windscreens or porous materials over the surface of the microphone to reduce the interaction between the moving air and the microphone's surface.
Puff and pop problems are more prevalent in small diameter microphones, especially when the microphone transducer is of the condenser type. Primarily, the greater problems for small diameter microphones result from air turbulence causing a higher net instantaneous total pressure on the surface of a small area microphone than on a larger area microphone. That is, on a microphone having a small area for receipt of sound pressure, there may be in any instance a preponderance of elevated pressure cells, or there may be rarified pressure cells, causing unwanted motion in the microphone sound receiving surface and hence unwanted puff or pop signals.
Conventional methods of reducing puff or pop noise in small diameter microphones are effective. However, a need has arisen for a technique of producing noise reduction that is more effective than currently used in small diameter microphone transducers in such application as, for example, a telephone or radio telephone handset. That is, a means is needed that is more effective than adding a windscreen or a foam (or similar) covering to the microphone transducer.